The fitness of David Silva ahead of next weekend's derby overshadowed the build-up to Manchester City's inconsequential Champions League match away to Shakhtar Donetsk.
Manager Pep Guardiola revealed on Tuesday the Spain playmaker suffered a knock in the latter stages of Sunday's victory over West Ham, a game in which he scored City's late winner.
The midfielder is now a doubt for Sunday's clash with arch-rivals Manchester United at Old Trafford.
City had already announced that Silva would not be travelling to Ukraine for Wednesday's final Group F game in Kharkiv but it was assumed he was being rested.
The nature of his problem remains unclear with Guardiola refusing to elaborate much when questioned on the issue at his pre-match press conference at the Metalist Stadium.
Guardiola said: "David had a little bit problems in the last minutes. We made a test after the game and I don't know if he is able to play on Sunday, so that's why he stayed there, to recover in Manchester."
Asked for further clarification on the injury, Guardiola said: "It's something, he was uncomfortable. It was too risky to play (Wednesday)."
There is nothing at stake for City in Kharkiv with top place in the group already assured.
As well as replacing Silva, there will be another enforced change with Kevin De Bruyne suspended but Guardiola may consider giving youngsters Phil Foden, Brahim Diaz and Tosin Adarabioyo a chance. All three have travelled with the squad.
But Guardiola insisted he will not be taking the game lightly. Victory would be City's 21st in succession in all competitions.
Guardiola said: "We travelled here to win the game, to make a good performance and show respect for the clubs and this competition. We are preparing to win the game and trying to do as much as possible to make a good game."
The game is critical for Shakhtar, who would secure a place in the last 16 by avoiding defeat.
Coach Paulo Fonseca said: "If we look at City's performances this season, I think we can call them, if not the best, then definitely one of the best teams in the world right now.
"I have had similar deciders in my career but this is the first time I have had such a game in the Champions League."